The purpose of this project is to study experimentally induced pulmonary fat embolism in laboratory animals. We shall use a model system developed in our laboratory in which injected labelled triglyceride emulsions accumulate in the vascular bed of the lung. We shall study the clearance and metabolism of these lipids as well as the enzymes that are involved. The mechanism of emboli clearance is complex but it does involve specific lung and blood lipoprotein lipases which are released from the surfaces of vascular endothelial cells. We shall use specific drugs in these studies such as heparin, dextran sulfate, heparan sulfate and inorganic phosphate polymers which promote clearance of the lung emboli by releasing lipoprotein lipases. We shall also use barbiturates such as phenobarbital, pentobarbital and thiopental and anticonvulsants such as phenytoin which we have found inhibit the release of these enzymes. Our studies are also projected to give important information regarding the origin of cell surface lipoprotein lipase in lung tissues and factors that affect its release. Parallel studies on the histological changes that occur in this syndrome will also be carried out on lung tissues at the electron microscopic level. The results of this research will yield fundamental data on clearance of pulmonary fat embolism and suggest a fundamental basis for rational drug treatment of this poorly understood but often lethal syndrome.